1. Field of the Invention
The present invention is directed towards a medical instrument such as, but not limited to, an obturator of the type associated with a trocar assembly and which includes an elongated shaft having a penetrating tip formed on one end thereof. The penetrating tip includes an exterior surface configuration structured to facilitate the forming of an access opening in bodily tissue in a manner which requires a minimum application of an inwardly directed, linear pushing force on the instrument, but rather relies on a back and forth or xe2x80x9creciprocalxe2x80x9d twisting motion. The configuration of the exterior surface of the penetrating tip is at least partially characterized by a perpendicular cross-section, extending along at least a majority of the length of the tip, having a circumferential configuration substantially in the form of an ellipse.
2. Description of the Related Art
In the medical field there are numerous instruments specifically designed to penetrate bodily tissue so as to provide access to internal body cavities or organs. More specifically, an initial and primary activity during the performance of surgery is the creation of an access opening into the body cavity at a predetermined surgical site. In the past, such access openings were formed by the creation of a substantially large incision through the body wall or outer tissue, wherein the size of the incision would depend on the type of surgery, and accordingly, the surgical instruments involved. On completion of the surgical procedure, the large incision would be closed using conventional techniques. However, due to the traumatic nature of such open surgical procedures, the period of time required of the patient to completely heal was significant. In addition, the pain or discomfort during such recuperative period was a serious problem.
Because of the above noted disadvantages, attempts have been made which were specifically directed towards new surgical procedures as well as instruments utilized in the support of such procedures. Currently, a popular alternative to open surgery is known as laparoscopic and/or endoscopic surgery, wherein a number of small openings, utilizing appropriate penetrating instruments, are formed to provide access into an intended body cavities. Unlike the large incision required during open surgery, the much smaller access openings facilitate healing following the surgical and, as expected, result in significantly less discomfort to the patient.
Depending on the type of endoscopic surgery being performed, the instrumentation used to form the one or more small access openings may vary. However, common to such medical penetrating instruments is the provision of a sharpened or otherwise configured penetrating tip. By way of example, instrumentation utilized in the performance of endoscopic surgery are commonly referred to as trocar devices or trocar assemblies. In conventional fashion, a trocar assembly normally includes a trocar tube or cannula and an obturator. Utilizing such instrumentation, access is gained to a body cavity or organ by penetrating the bodily tissue defining the exterior wall of the patient, in order that laparoscopic or arthroscopic surgery may be performed. The obturator, serving as the penetrating instrument, passes along or is positioned within the lumen of the cannula or trocar tube. The aforementioned penetrating tip is formed on the distal end of the obturator. The penetrating tip of the obturator is forced through the skin until entry to the body cavity has been established. The trocar tube, serving as an access cannula is then forced through the perforation, formed by the obturator and the obturator is withdrawn, leaving the trocar tube or cannula as an access or passage way to the intended body cavity or organ.
In related endoscopic surgical techniques, the penetrating instrument may be used with the trocar tube or surgical access cannula or may be used as a xe2x80x9cstand alonexe2x80x9d device to puncture through the skin and underlying bodily tissue for purposes of forming the small access opening and inserting a separate access cannula, catheter or other surgical instrument into communication with the now accessed body cavity or organ.
The aforementioned substantially conventional medical penetrating instruments normally include a penetrating tip having a sharpened point spaced distally from a base which is connected to one end of the obturator or penetrating instrument. Also the conventional structure of such penetrating tips typically include either a conical or a multi-sided, substantially pyramidal configuration. The design and structuring of penetrating tips for the type of medical instruments described herein is important for the efficient formation of the small access opening, as set forth above. However, such penetrating tips should efficiently and cleanly create the access opening in a manner which serves to at least partially dilate or enlarge the opening, as the shaft of the obturator or other penetrating instrument passes through the bodily tissue. However, it is equally important that a minimal amount of damage, in terms of severing or cutting, be done to the contiguous body tissue surrounding the access opening during the initial penetration, as well as the enlargement of the access opening, as the penetrating instrument is positioned into direct communication with the intended body cavity or organ.
Accordingly, there is a need in the field of medical instrumentation for a penetrating instrument which may be used independently or which may be associated with a trocar device or assembly, along with other associated components such as, but not limited to, a trocar tube or access cannula. Such an improved penetrating instrument should be designed to include an improved penetrating tip which is structured to facilitate a clean formation of a small access opening through the puncturing of the body wall. The penetrating tip should preferably include an exterior surface, as well as a distal extremity or apex, cooperatively or collectively configured to enlarge the access opening and effectively separate or dilate the bodily tissue contiguously disposed to the access opening, as the penetrating instrument is advanced therethrough into communicating relation with a predetermined body cavity or organ. Further, the design and structuring of the penetrating tip should be such as to form the access opening, in the manner set forth above, without causing any unnecessary cutting, severing or damaging of the bodily tissue during the formation of the access opening.
The present invention is directed towards a penetrating instrument of the type used in the medical field and which may or may not be embodied in a trocar assembly, wherein the penetrating instrument would be specifically referred to as the obturator. Whether or not embodied in a trocar assembly, the penetrating instrument of the present invention comprises a penetrating tip specifically designed and structured to create a small access opening in the body wall or outer tissue of a patient, so as to establish communication with an internal body cavity or organ on which a surgical procedure is to be performed.
Further, the penetrating tip of the present invention is designed and structured to effectively create the small access opening by puncturing the outer body tissue or body wall of a patient in a manner which serves to separate and enlarge the created access opening, as the penetrating instrument passes therethrough into communication with the body cavity. The design and overall structural configuration of the penetrating tip, as will be explained in greater detail hereinafter, is such as to accomplish an effective separation of the bodily tissue being penetrated and at least a minimal dilation of such tissue in a manner which creates a minimal amount of cutting and severing of the body tissue, and thereby, minimizes the damage to the body tissue contiguous to the access opening during its formation or during the passage of an access cannula or other instruments therethrough.
More specifically, the penetrating instrument of the present invention, whether associated with a trocar assembly or used independently thereof, comprises an elongated shaft having a penetrating tip integrally or otherwise secured to an outer end thereof. The penetrating tip includes a base which is integrally or otherwise fixedly secured to the outer end of the shaft. In addition, the penetrating tip includes a distal extremity configured to define an apex. For purposes of clarity, the term xe2x80x9capexxe2x80x9d is meant to describe a variety of different configurations, which may vary from a sharpened point to a tapered locale, which may be defined by the converging of the exterior surface of the penetrating tip extending continuously from the base to the distal extremity. In any event, the apex may assume a variety of different configurations, all of which are specifically intended to facilitate the penetration of the body wall or outer tissue in a manner which minimizes any damage being done to the contiguous tissue surrounding a formed access opening created by the penetration or puncturing of the body tissue.
The aforementioned exterior surface of the penetrating tip extends from a convergent locale, defined by the aforementioned apex, continuously to the base of the penetrating tip located at and defining the integral or otherwise fixed junction between the penetrating tip and the outer most end of the shaft of the penetrating instrument. Further, the apex of the penetrating tip, in different embodiments of the present invention, may be disposed coincident to a linear extension of a central longitudinal access of the shaft or, alternatively, may be spaced laterally outward or in an off-set, somewhat eccentric position relative to a linear extension of the central longitudinal access of the shaft of the penetrating instrument.
Common to each of the aforementioned embodiments is a shaping of the exterior surface of the penetrating tip in structural cooperation with the distal extremity or apex thereof, such that a cross-section of the penetrating tip, oriented perpendicular to the central longitudinal access of the shaft and extending along at least a majority of the length of the penetrating tip, is defined by a substantially elliptical circumferential configuration.
It is emphasized that the referred to perpendicular cross-section of each of the penetrating tips of the above referred to alternative embodiments, does not necessarily comprise a circumferential configuration defined by a xe2x80x9ctrue or precisexe2x80x9d ellipse. In one or more embodiments of the penetrating tip of the present invention, the exterior surface thereof comprises at least minimally segregated surface segments, somewhat oppositely disposed, and separated by two elongated edges extending from the apex towards the base in a curved configuration. In addition, the opposed edges may be more specifically defined by cutting edges which, along with the distal extremity of the penetrating tip, serve to facilitate the initial puncture of the body wall or bodily tissue, as well as a separation or dilation of the contiguous tissue surrounding the access opening.
Accordingly, the design and structure of the penetrating tip of the present invention, whether or not embodied in a trocar device, includes an exterior surface configuration and a distal extremity shaped to enlarge and/or separate bodily tissue during the insertion of the penetrating instrument into the body wall of the patient. The preferred exterior surface configuration penetrates the designated bodily tissue in a manner which minimizes damage and/or cutting or severing of the tissue during the passage of the penetrating tip, as well as an adjacent portion of the shaft of the penetrating instrument passing through the created access opening.
These and other objects, features and advantages of the present invention will become more clear when the drawings as well as the detailed description are taken into consideration.